package com.zenithmind.document.service.impl;

import com.zenithmind.document.mapper.DocumentMapper;
import com.zenithmind.document.pojo.domain.Document;
import com.zenithmind.document.service.DocumentAccessControlService;
import com.zenithmind.document.service.DocumentPermissionService;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;

import java.util.ArrayList;
import java.util.List;

/**
 * 文档访问控制服务实现类
 * 遵循单一职责原则：专注于访问控制逻辑
 * 遵循依赖倒置原则：依赖抽象接口而不是具体实现
 * 遵循开闭原则：通过策略模式支持扩展新的权限检查规则
 * 
 * @author ZenithMind Team
 * @since 2025-01-09
 */
@Slf4j
@Service
@RequiredArgsConstructor
public class DocumentAccessControlServiceImpl implements DocumentAccessControlService {

    private final DocumentMapper documentMapper;
    private final DocumentPermissionService documentPermissionService;

    @Override
    public Boolean hasPermission(String documentId, String userId, String action) {
        log.info("检查文档访问权限: documentId={}, userId={}, action={}", documentId, userId, action);
        
        try {
            // 1. 检查文档是否存在
            Document document = documentMapper.selectById(documentId);
            if (document == null) {
                recordAccessAttempt(documentId, userId, action, false, "文档不存在");
                return false;
            }
            
            // 2. 检查是否为所有者
            if (isOwner(documentId, userId)) {
                recordAccessAttempt(documentId, userId, action, true, "所有者权限");
                return true;
            }
            
            // 3. 检查文档是否公开且操作为查看
            if (isPublic(documentId) && "view".equals(action)) {
                recordAccessAttempt(documentId, userId, action, true, "公开文档查看");
                return true;
            }
            
            // 4. 检查用户是否在访问列表中
            if (isInAccessList(documentId, userId)) {
                // 进一步检查具体权限
                Boolean hasSpecificPermission = documentPermissionService.checkUserPermission(documentId, userId, action);
                recordAccessAttempt(documentId, userId, action, hasSpecificPermission,
                    hasSpecificPermission ? "权限列表允许" : "权限列表拒绝");
                return hasSpecificPermission;
            }
            
            // 5. 检查角色权限
            Boolean hasRolePermission = hasRolePermission(documentId, userId, action);
            recordAccessAttempt(documentId, userId, action, hasRolePermission, 
                hasRolePermission ? "角色权限允许" : "角色权限拒绝");
            return hasRolePermission;
            
        } catch (Exception e) {
            log.error("检查文档权限时发生错误: documentId={}, userId={}, action={}", documentId, userId, action, e);
            recordAccessAttempt(documentId, userId, action, false, "系统错误: " + e.getMessage());
            return false;
        }
    }

    @Override
    public Boolean isOwner(String documentId, String userId) {
        log.debug("检查文档所有权: documentId={}, userId={}", documentId, userId);
        
        Document document = documentMapper.selectById(documentId);
        return document != null && userId.equals(document.getCreatorId());
    }

    @Override
    public Boolean isPublic(String documentId) {
        log.debug("检查文档是否公开: documentId={}", documentId);
        
        Document document = documentMapper.selectById(documentId);
        // accessLevel: 0=私有, 1=公开, 2=部门, 3=指定用户
        return document != null && document.getAccessLevel() != null && document.getAccessLevel() == 1;
    }

    @Override
    public Boolean isInAccessList(String documentId, String userId) {
        log.debug("检查用户是否在访问列表中: documentId={}, userId={}", documentId, userId);
        
        // 实现检查用户是否在文档的访问列表中
        try {
            // 1. 查询 document_permission 表检查直接权限
            boolean hasDirectPermission = documentPermissionService.checkUserPermission(documentId, userId, "view");
            if (hasDirectPermission) {
                return true;
            }

            // 2. 检查用户是否在文档的访问白名单中
            boolean inWhitelist = checkUserInAccessWhitelist(documentId, userId);
            if (inWhitelist) {
                return true;
            }

            // 3. 检查用户是否通过部门权限获得访问权限
            boolean hasDepartmentAccess = checkDepartmentAccess(documentId, userId);
            if (hasDepartmentAccess) {
                return true;
            }

            log.debug("用户不在文档访问列表中: documentId={}, userId={}", documentId, userId);
            return false;

        } catch (Exception e) {
            log.error("检查用户访问列表失败: documentId={}, userId={}", documentId, userId, e);
            return false;
        }
    }

    @Override
    public Boolean hasRolePermission(String documentId, String userId, String action) {
        log.debug("检查角色权限: documentId={}, userId={}, action={}", documentId, userId, action);
        
        // 实现基于角色的权限检查
        try {
            // 1. 获取用户角色列表
            java.util.List<String> userRoles = getUserRoles(userId);
            if (userRoles == null || userRoles.isEmpty()) {
                log.debug("用户无角色: userId={}", userId);
                return false;
            }

            // 2. 检查每个角色是否有对应的文档权限
            for (String roleId : userRoles) {
                boolean hasRolePermission = documentPermissionService.checkRolePermission(documentId, roleId, action);
                if (hasRolePermission) {
                    log.debug("角色权限检查通过: documentId={}, roleId={}, action={}", documentId, roleId, action);
                    return true;
                }
            }

            // 3. 检查是否有通用角色权限（如：所有用户、已认证用户等）
            boolean hasGeneralRolePermission = checkGeneralRolePermission(documentId, action);
            if (hasGeneralRolePermission) {
                log.debug("通用角色权限检查通过: documentId={}, action={}", documentId, action);
                return true;
            }

            log.debug("角色权限检查失败: documentId={}, userId={}, action={}", documentId, userId, action);
            return false;

        } catch (Exception e) {
            log.error("角色权限检查失败: documentId={}, userId={}, action={}", documentId, userId, action, e);
            return false;
        }
    }

    @Override
    public List<String> getEffectivePermissions(String documentId, String userId) {
        log.info("获取用户对文档的有效权限: documentId={}, userId={}", documentId, userId);
        
        List<String> permissions = new ArrayList<>();
        
        // 基本权限检查
        String[] basicActions = {"view", "download", "edit", "delete", "convert", "share"};
        
        for (String action : basicActions) {
            if (hasPermission(documentId, userId, action)) {
                permissions.add(action);
            }
        }
        
        return permissions;
    }

    @Override
    public void recordAccessAttempt(String documentId, String userId, String action, Boolean success, String reason) {
        log.info("记录访问尝试: documentId={}, userId={}, action={}, success={}, reason={}", 
            documentId, userId, action, success, reason);
        
        // 实现访问尝试记录
        try {
            // 创建访问尝试记录
            AccessAttemptRecord record = new AccessAttemptRecord();
            record.setDocumentId(documentId);
            record.setUserId(userId);
            record.setAction(action);
            record.setSuccess(success);
            record.setReason(reason);
            record.setAttemptTime(java.time.LocalDateTime.now());
            record.setIpAddress(getCurrentUserIpAddress());
            record.setUserAgent(getCurrentUserAgent());

            // 保存到访问日志表
            saveAccessAttemptRecord(record);

            // 如果访问失败，可能需要额外的安全处理
            if (!success) {
                handleFailedAccessAttempt(documentId, userId, action, reason);
            }

            log.debug("访问尝试记录保存成功: documentId={}, userId={}, action={}, success={}",
                    documentId, userId, action, success);

        } catch (Exception e) {
            log.error("记录访问尝试失败: documentId={}, userId={}, action={}", documentId, userId, action, e);
        }
    }

    // ========== 私有辅助方法 ==========

    /**
     * 检查用户是否在访问白名单中
     */
    private boolean checkUserInAccessWhitelist(String documentId, String userId) {
        // TODO: 实现访问白名单检查
        // 这里应该查询文档的访问白名单配置
        return false;
    }

    /**
     * 检查部门访问权限
     */
    private boolean checkDepartmentAccess(String documentId, String userId) {
        // TODO: 实现部门访问权限检查
        // 这里应该根据用户部门和文档的部门权限配置来判断
        return false;
    }

    /**
     * 获取用户角色列表
     */
    private java.util.List<String> getUserRoles(String userId) {
        // TODO: 实现获取用户角色逻辑
        // 这里应该调用用户服务获取用户的角色列表
        return new java.util.ArrayList<>();
    }

    /**
     * 检查通用角色权限
     */
    private boolean checkGeneralRolePermission(String documentId, String action) {
        // TODO: 实现通用角色权限检查
        // 检查如"所有用户"、"已认证用户"等通用角色权限
        return false;
    }

    /**
     * 获取当前用户IP地址
     */
    private String getCurrentUserIpAddress() {
        // TODO: 实现获取当前用户IP地址
        // 这里应该从请求上下文中获取IP地址
        return "127.0.0.1";
    }

    /**
     * 获取当前用户代理
     */
    private String getCurrentUserAgent() {
        // TODO: 实现获取当前用户代理
        // 这里应该从请求上下文中获取User-Agent
        return "Unknown";
    }

    /**
     * 保存访问尝试记录
     */
    private void saveAccessAttemptRecord(AccessAttemptRecord record) {
        // TODO: 实现保存访问尝试记录
        // 这里应该保存到数据库的访问日志表
        log.info("保存访问尝试记录: {}", record);
    }

    /**
     * 处理失败的访问尝试
     */
    private void handleFailedAccessAttempt(String documentId, String userId, String action, String reason) {
        // TODO: 实现失败访问尝试的处理
        // 可能包括：记录安全日志、触发安全警报、限制访问等
        log.warn("处理失败的访问尝试: documentId={}, userId={}, action={}, reason={}",
                documentId, userId, action, reason);
    }

    /**
     * 访问尝试记录内部类
     */
    private static class AccessAttemptRecord {
        private String documentId;
        private String userId;
        private String action;
        private Boolean success;
        private String reason;
        private java.time.LocalDateTime attemptTime;
        private String ipAddress;
        private String userAgent;

        // Getters and Setters
        public String getDocumentId() { return documentId; }
        public void setDocumentId(String documentId) { this.documentId = documentId; }

        public String getUserId() { return userId; }
        public void setUserId(String userId) { this.userId = userId; }

        public String getAction() { return action; }
        public void setAction(String action) { this.action = action; }

        public Boolean getSuccess() { return success; }
        public void setSuccess(Boolean success) { this.success = success; }

        public String getReason() { return reason; }
        public void setReason(String reason) { this.reason = reason; }

        public java.time.LocalDateTime getAttemptTime() { return attemptTime; }
        public void setAttemptTime(java.time.LocalDateTime attemptTime) { this.attemptTime = attemptTime; }

        public String getIpAddress() { return ipAddress; }
        public void setIpAddress(String ipAddress) { this.ipAddress = ipAddress; }

        public String getUserAgent() { return userAgent; }
        public void setUserAgent(String userAgent) { this.userAgent = userAgent; }

        @Override
        public String toString() {
            return "AccessAttemptRecord{" +
                    "documentId='" + documentId + '\'' +
                    ", userId='" + userId + '\'' +
                    ", action='" + action + '\'' +
                    ", success=" + success +
                    ", reason='" + reason + '\'' +
                    ", attemptTime=" + attemptTime +
                    ", ipAddress='" + ipAddress + '\'' +
                    ", userAgent='" + userAgent + '\'' +
                    '}';
        }
    }
}
